Patent GB-865391-A (GB)
Title: Improvements in or relating to thermal insulator material
Inventor: BAUER STEFAN GEORGE
IPC: F17C13/00
Filed: 1956-07-26
Abstract: A thermal insulator is formed from a mouldable and settable resinous composition which is internally multicellular and is contained within a gas-tight envelope, the individual cells being closed and containing substantially completely a selected vapour or gas whereby when the insulator is employed as heat insulation for a space at a temperature below the condensation temperature of the vapour or gas condensation occurs to create a high degree of vacuum within the cells.  Polystyrene and polytrifluoromonochloroethylene are suitable resinous materials and water-vapour or carbon dioxide may be the material within the cells.  An absorbent for the gas or vapour, such as activated p  carbon may also be present in the resin.  The envelope is suitably of thin flexible metal.  The gas or vapour-filled cells may be formed by use with the resin of a foaming agent which generates the selected vapour or gas.  An alternative method comprises the steps of producing a multicellular material from a mouldable and settable resinous composition whereof the cells are closed and have thin walls, enclosing the multicellular material in a gas-tight envelope (i.e. an envelope through which gas will not diffuse), connecting the envelope to evacuating means to reduce the pressure within the cells, thereafter connecting the envelope to a source of vapour or gas which is condensed when the insulator is used to insulate a space at a temperature below the condensation temperature of the gas or vapour and allowing the gas or vapour to diffuse into the cells of the material until a predetermined pressure is reached, again evacuating the envelope and again connecting the envelope to the source of vapour or gas and allowing the vapour or gas to diffuse into the cells until a predetermined pressure is reached, and then sealing the envelope. The evacuation and diffusion steps can be carried out more than twice.  The insulator can be used for tanks containing low temperature liquid fuels such as liquid hydrogen, oxygen or methane.ALSO:A thermal insulator is formed from a mouldable and settable resinous composition which is internally multicellular and is contained within a gas-tight envelope, the individual cells being closed and containing substantially completely a selected vapour or gas whereby when the insulator is employed as heat insulation for a space at a temperature below the condensation temperature of the vapour or gas condensation occurs to create a high degree of vacuum within the cells.  Polystyrene and polytrifluoromonochloroethylene are suitable resinous materials and water-vapour or carbon dioxide may be the material within the cells. An absorbent for the gas or vapour, such as activated carbon may also be present in the resin.  The envelope is suitably of thin flexible metal.  The gas or vapour-filled cells may be formed by use with the resin of a foaming agent which generates the selected vapour or gas. An alternative method comprises the steps of producing a multicellular material from a mouldable and settable resinous composition whereof the cells are closed and have thin walls, enclosing the multicellular material in a gas-tight envelope (i.e. an envelope through which gas will not diffuse), connecting the envelope to evacuating means to reduce the pressure within the cells, thereafter connecting the envelope to a source of vapour or gas which is condensed when the insulator is used to insulate a space at a temperature below the condensation temperature of the gas or vapour and allowing the gas or vapour to diffuse into the cells of the material until a predetermined pressure is reached, again evacuating the envelope and again connecting the envelope to the source of vapour or gas and allowing the vapour or gas to diffuse into the cells until a predetermined pressure is reached, and then sealing the envelope. The evacuation and diffusion steps can be carried out more than twice.  The insulator can be used for tanks containing low temperature liquid fuels such as liquid hydrogen, oxygen or methane.